Subtractive mental arithmetic.

Subtract the integer and add:

For example; 52-7 = 45, as follows: change "7" to "10-3"; Then, 52-10+3 = 45;

Subtraction of dislocation number;

The difference between ten digits and single digits is multiplied by 9.

For example; 83-38=45; So, 8-3 = 5, 5x9 = 45.

For example; 97-79 = 18, so 9-7 = 2, 2x9 =18;

And so on.

Subtract multiple numbers in succession.

Such as 387-50-42-31= 264; Do a simple calculation first, 387-50 = 337, and then add 42 and 3 1 to get 73; Then, 337-73 can become 337-80+7 = 264.

Extended data:

Fast center is the only way to perform simple operations without any physical objects, abacus, fingers, chessboard and charts.

The arrangement and difficulty of the textbook "Fast Mental Arithmetic" is a fast calculation that closely follows the syllabus of primary school mathematics and integrates with junior high school algebra, which is simpler than the primary school textbook. Simplify written calculation and strengthen oral calculation. It is simple, easy to learn and interesting. After a short period of training, primary school students can write answers directly by adding, subtracting, multiplying and dividing, not vertically.

Fast heartbeat algorithm

I have learned all the multiplication, division, addition and subtraction of any multi-digit number above grade three.

Addition and subtraction of high two digits, multiplication of two digits, division of one digit.

First grade, multi-digit addition and subtraction.

In kindergarten, children in large classes can learn to add and subtract multiple digits, such as 5869+35 16, subtract multiple digits and abdicate multiple digits. For example, 8 185-6938 and so on. All the addition and subtraction problems in primary school math textbooks will be solved by your children. Tailored for preschool children.

Pass the elementary school oral calculation in advance. It is helpful for children to learn mental arithmetic quickly in kindergarten to go to primary school in the future. Fast mental arithmetic combines the characteristics of mental arithmetic, verbal arithmetic and written arithmetic, and pays more attention to excellent verbal arithmetic skills, which will greatly increase children's self-confidence and lay a good foundation for their future development.

Children no longer use draft paper to do their homework, but write answers directly.

Fast mental arithmetic is different from abacus mental arithmetic and palm mental arithmetic. Mainly through certain rules in textbooks, children are trained to operate quickly in addition, subtraction, multiplication and division. "Quick mental arithmetic" is helpful to improve the order, logic and sensitivity of children's thinking and behavior, and train children's eyes, hands and brain to react synchronously and quickly. The calculation method is consistent with mathematics in primary and secondary schools, so it is very popular with parents of young children.

Baidu Encyclopedia-Fast Heartbeat Algorithm